What is Querying? n It is asking questions about the data in the database and manipulating or combining the data in different ways n We can isolate certain rows in tables, we can isolate certain columns in tables, we can join tables together, we can create calculations based on various data items, etc.

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Querying/Information Retrieval Requirements for effective querying 1. A database that is well-designed n If tables are not fully relational or incompletely specified, or if conceptual model has not been correctly converted into relational form, querying will be difficult or impossible 2. A query developer who understands the table structures and the nature of the data in the tables 3. A query developer who understands the desired query output 4. A query developer who has good logic and reasoning skills 5. A query developer who knows the querying language used to retrieve information from the enterprise database